Hydrometer



Dec. 3, 1935. o. H. FAlRcHlLD 2,023,195

HYDROMETER Filed Nov. 21, 195o 2 sheets-sheet'l ZLL Patented Dec. 3, 1935 UNITED STATES PATENT OFFICEl 2.023.196 nrnnoME'rEn Application November 21, 1930, Serial No. 497,117

2 Claims.

This invention relates to an improved hydrometer for determining the specific gravity of a liquid, and relates more particularly to determining the specific gravity of a stream of liquid 5 maintained under substantially atmospheric, subatmospherc or superatmospheric pressures.

One of the objects of my invention is to provide an improved form of hydrometer, particularly useful in determining the specific gravity of a stream of liquid at any instant. For example,

it is often advantageous' to determine the character, with respect to specific gravity, of a hydrocarbon distillate from a pressure still or rerun still as an index to the operation of the still and to assist in regulating the quality of the distillate produced.

Various preferred constructions of the hydrometer adapted for use under superatmospheric, sub-atmospheric or atmospheric pressures are illustrated in the accompanying drawings, which are more or less diagrammatic, and in which,

Fig. l is a sectional, side-elevational view of one form of my invention, designed for superatmospheric pressure operations;

Fig. 2 is a sectional, side-elevational view oi a modied form of my invention, designed for atmospheric operations;

Fig. 3 is a sectional, side-elevational view of another modification of my device; and

Fig. 4 is a top plan view of the form of device shown in Fig. 3.

Referring to Figfl, there is shown a main or lower body portion I, provided with a removable base or closure member 2, inlet pipe 3 and outlet pipe 4, for containing a liquid 5, the specic gravity of which is to be measured, and which iixedly engages a suitable support or bracket 6; and a secondary or upper body portion 1 in iixed relation with a suitable support or bracket 8. The

body portions I and 1 may be constructed of any suitable material, preferably a metal, of suiclent strength to withstand any desired pressure to which the apparatus may be subjected. Positioned intermediate the upper body portion 1 and the lower body portion I is a glass tube 9, of suflicient strength and thickness to withstand any desired superatmospheric pressure.

An hydrometer I D, of any conventional type, depending upon the character of the liquid to be tested, may oat in the liquid 5 within a chamber II of the body I. The neck of said hydrometer I0 may extend upwardly through tube 9, into the upper body member 1, rendering it observable through said tube 9. If desired, a reinforcing shell (not shown), of any suitable material, preierably metal, may be provided to surround said tubular glass 9, although a tubular glass member, concentric with the upper or neck portion of the hydrometer I0 to provide a restricted passage therebetween, will be suiiicient for most 5 pressures.

The upper and lower extremities of the tubular glass 9 are adapted to be disposed in non-leaking relationship at their point of juncture with the lower and upper body casings I and'1, respec- 10 tively. To insure such non-leaking relationship,

I may provide a packing I2, maintained under compression by means of packing glands I3. If

it be desired to remove, or for any purpose change the tubular glass 9, this may be accomplished 15 by merely unscrewing the packing gland I3.

In order to insure a more accurate reading of the calibrations I4 on the neck of the hydrometer I0, I provide a hairline I5 on the tubular glass 9. To conveniently clean the inner sur- 20 faces of the tube 9, a plug I6 may be provided in the upper end of the member 1, the removal of which provides access to the interior of said tube.

In order to prevent lateral movement of the lower body portion of the hydrometer I0 situated 25 within the chamber I I, and a consequent binding of the neck of the hydrometer within the tube 9, I may provide a plurality of guiderods I1 which may, if desired, be mounted upon the lower closure member 2 of the body I. The rods I1, 30 as can be readily seen, will confine the movement of the hydrometer I0 in a vertical direction. To prevent the body of the hydrometer I0 from adhering to said guiderods I1, the rods may preferably be constructed of a relatively frictionless 35 material, such as glass, or any highly polished, non-corrosive metal or an alloy of iron or steel. Any desired number of guiderods I1 may be employed, depending upon the size of the hydrometer to be guided, and the nature of the liquid 40 under test.

If it be desired to change the hydrometer Ill, or repair or alter the guide rods I1, this may be accomplished by removal of the base or lower closure member 2 of the body portion I. 45

At the upper limits of the casing I, and adapted to receive the overow of liquid from' the chamber II. I may provide a reservoir I8 and compartment I 9 in communication with the chamber Il. Disposed within the reservoir I8 ,is a well 50 20, adapted to receive and hold a temperature measuring device 2I, to indicate the temperature of the liquid under test. Temperature measuring device 2| may be of any conventional type, uh as a thermometer or thermo-couple. 55

In order to control the liquid level in the chamber I I and the reservoir I8, I provide a liquid level control device 22, adapted to be disposed at the entrance of the compartment I9, to threadedly engage and bridge the upper longitudinal wall of said compartment I9. Liquid level control member 22 may be raised or lowered, as desired, through movement of the downwardly extending rod or arm 23, by means of the handle 24. 'Ihe arm or rod 23 is suitably packed, as shown at 25, said packing being compressed by movable gland 26. Suitable inlet and outlet ports 21 and 28 are provided in the liquid level control member 22, providing for passage of liquid therethrough.

In the modication shown in Fig. 2, and which may be employed in atmospheric pressure operations, substantially the same general type of apparatus is employed as in Fig. 1, with the exception that the apparatus employed, may, if desired, be of a lighter and less expensive construction. In addition, the following differences appear:-

The liquid level in the chamber II' of the casing I is maintained constant by means of the permanent overilow 01 liquid level walls 29. Adapted to receive said overflow liquid, and arranged concentric with and surrounding the upper portion of the casing I', and integral therewith, is a reservoir 30, from which overflow liquid passes through outlet pipe 4, controlled by a. valve (not shown).

Since lower temperatures may be employed in atmospheric operations, a suitable temperature measuring device 3I, of any conventional type, may have its base immersed in the liquid in' the reservoir 30. A suitable plug 32, readily removable from the casing I' and through which the temperature measuring device 3| passes, is provided for supporting said device 3l in any desired position. The plug 32 may be of rubber or other resilient material, adapted for ready removal and replacement.

A tubular glass 33 of any desired thickness, may have its base suitably packed in a closure member 34, threaded for removal from the body or casing I. 'I'he closure member 34 is apertured throughout its central portion in order toprovide fo'r reception of the base of the tubular glass 33 through which the upper portion or neck of the hydrometer I may be disposed.

Extending verticallyfrom said closure member 34, and parallel to said tubular glass 33, I may provide metal support rods 35, of any desired type, bearing horizontal metal closure cap 36 adapted to be disposed over and close the' upper end of the tubular glass 33, the juncture of said closure member and tubular glass being suitably packed as at 3l. The cap 36 is held in fixed relation with the tubular glass 33 by means of the nuts or bolts 38, threaded to the rods 35.

The tubular glass 33 may be of any desired length whenused in this modification of the invention, since the' care incident to a pressure operation and the requirement as to strength and structure of the glass is not as important. For this reason, a wider range of observance of the calibrations I4 of the hydrometer I0 is possible. A suitable cleaning plug 39, of rubber or other resilient material, and which is readily removable from the cap 36, is provided in order to clean the interior surfaces of the tubular glass 33.

mospheric pressures are used. It will be seen that the upper casing I of Fig. 1 has been dispensed with, and in. lieu thereof, I may provide vertical rods 35', substantially similar to those shown in Fig. 2. The vertical rods 35', by means of the bolts 38', secure a horizontal metal closure cap 40, bearing packing 4I, to the upper end of the tubular glass 42, thereby insuring a nonleaking, pressure-resisting juncture.

Inasmuch as the apparatus illustrated in this modified form of the invention may be subjected to high temperatures and pressures, care must be taken in selecting a tubular glass member 42 of sumcient strength to withstand the desired pressures and temperatures; also, a suitable temperature indicating or recording device 43, either a thermometer or thermo-couple, or the like, must be selected to accord with such temperatures and pressures. For illustration, I have shown in this modification a temperature measuring device 43 withits base immersed in the liquid in the chamber II', disposed within a. suitable support 44 within the casing I". Obviously, any other conventional temperature indicating or recording device may be employed.

As an example of a method of operation of my device as represented in Fig. 1, liquid at any desired temperature, and under atmospheric,

super-atmospheric, or sub-atmospheric pressure, enters the chamber II tangentially through inlet pipe 3, controlled by a valve (not shown). This tangential entrance of the liquid into the chamber II imparts a swirling action thereto as it rises within said chamber, resulting in a revolving action or rotation of the hydrometer I0 to prevent adhesion of its surfaces to the surfaces of the guiderods II, rendering said hydrometer operative and insuring an accurate indication of the gravity of the liquid at the hair-line I5 on the glass tube 9, when the appropriate level'of the liquid has been reached.

Continuing its Urise throughout the chamber I I, the liquid will ultimately overflow into the communicating reservoir I8 within which is disposed the well containing temperature indicating device 2|, through which medium a temperature reading is taken of the liquid under test. Governed by the height at which the liquid level control 22 may be set, the rising liquid, upon lling the reservoir I8, will continue in its upward travel until it has equalled the height of the liquid level control 22, and upon exceeding the level there set, will overflow into said liquid level controlI through port 21 and pass into compartment I9 through outlet ports 28 in said liquid level control. The liquid will flow out of said compartment I9 through outlet pipe 4, controlled by a suitable valve (not shown). It is thus apparent that a raising or lowering of said liquid level control 22 will result in a corresponding increase or decrease in the liquid level maintained in the chamber II and reservoir I8.

To calibrate those embodiments of my invention shown in Figs. 1 and 3, a liquid of known gravity, at a given temperature, may be introduced into the chambers I I or II', and the liquid level may be so adjusted as to obtain registration of a datum point upon the calibrated neck of the hydrometer and the hairline. Obviously, all subsequent; gravity readings, taken at the same temperature, will be accurate with reference to said setting. In superatmospheric operation, relatively high temperatures may be employed, and hence a false gravity reading may be obtained which must be corrected for temperatures. To

obviate these subsequent corrections, the correcread directly from the hydrometer. When the device is used in connection with a distiuing apparatus in which steam isJ used or if for any other reason the distillate or other oil undergoing gravity determination contains water, a water trap of any well known type should be provided in the line leading to the gravity indicating device'or a drain maybe provided in the lower body portion of the device to permit the periodic removal of accumulated water.

l5 I claim as my invention:-

1. A device for measuring the density ot liquid comprising in combination, a liquid chamber having curved walls, an inlet and outlet for said chamber, an hydrometer disposed in said chamber and means associated with said inlet to introduce liquid tangentially to the walls oi.' said chamber. A

2. A device for measuring the density of liquid comprising in combination, a liquid chamber having curved walls, a liquid inlet disposed tangentially to the walls of said chamber to impart a rotary'motion to the introduced liquid, a liquid outlet, and a rotatable hydrometer disposed in said chamber. l

. OSCAR H. FAIRCHILD. 

